Methods and systems of the above type are well-known in various technical fields, for joining the ends of a band-shaped product into an endless band. Such technical fields include wood processing industries in which endless wires and felts are used, e.g., for drying paper webs in paper machines. Cellulose and paper board machines are further known applications.
The joining of the ends of a band-shaped product, such as a wire or felt, is of essential importance in wood processing industries in particular, since wires or felts woven endless are always very difficult to mount in place due to the fact that it is necessary to disassemble the supporting structure of the rolls on one side to be able to place the wire or felt in a paper machine, for instance. The disassembly and assembly of such structures is difficult, and plenty of room is required at the side of the machine as the wire or felt is mounted from the side. Furthermore, endless felts and wires are heavy and large, wherefore they are difficult to handle.
For this reason, it is customary to weave the wire or felt into a band-shaped product the ends of which are not joined until in the machine. It is thereby possible to draw the wire or felt on the rolls in the operating direction of the machine. Various methods and arrangements have been developed for temporarily joining the ends of the wire or felt e.g. in a paper machine After the temporary joining, a permanent joint is formed and the temporary joint is opened.
Known solutions include the method and means disclosed in Swedish Published Specification 435,207 for joining the ends of a band-shaped product. This known solution utilizes a so called zipper principle, whereby ribbons are fastened adjacent to the ends of the product to form the zipper halves The ends of the product can thereby be joined by means of a connecting slide which functions in the same way as a conventional zipper slide. After the forming of the temporary joint, the proper joint is formed e.g. by passing a joint thread through loops provided at the ends of the product. The zipper parts are naturally removed after the permanent joint is completed.
Another example of known solutions would be the device disclosed in Finnish Patent Application 840,804. In this known solution the ends of a band-shaped product are provided with interlocking clasp means by means of which the ends are joined temporarily. After the temporary joint has been formed in this way, the permanent joint is formed e.g. in a manner described in connection with the preceding known solution. After the permanent joint has been formed, the clasp means are removed from the band-shaped product.
A disadvantage of these known solutions is, for instance, that the locking of the ends of the band-shaped product may open when used as an aid in the mounting. A further disadvantage is that the adjustment is difficult, i.e. the two sides of the joint are difficult to get properly in alignment, wherefore the joint thread or wire is difficult to pass in place. In addition, if the joint is not quite straight, the joining is difficult to be carried out by means of known solutions. Also, the use of known solutions is difficult and laborious, as a result of which the change of a felt, for instance, is slow. Prior solutions are suitable for temporary joining only, whereby the permanent joint always has to be made by means of different joining means.
The object of the invention is to provide a method and an arrangement for joining the ends of a band-shaped product, which avoid the disadvantages of the prior art. This is achieved by means of a method according to the invention which is characterized in that the alignment strips are positioned side by side in such a way that the outer surfaces of the bottoms of the U-shaped elements are in alignment and that the alignment strips so positioned are interlocked by means of a locking strip to be passed in place from the side of the band-shaped product in the longitudinal direction of the alignment strips so as to get engaged with the U-shaped elements. An arrangement according to the invention, in turn, is characterized in that the arrangement comprises a locking strip provided with two members arranged to simultaneously engage with the U-shaped elements of the alignment strips positioned side by side with the outer surfaces of the bottoms of the U-shaped elements in alignment, thus locking the alignment strips to each other.
An advantage of the solution according to the invention is above all that the locking is simple as it can be effected from the side of the machine so that the locking strip automatically draws together the ends of the product. A further advantage is that the joint cannot open after the locking, not even when the product is loose. The invention can also be used for providing a permanent joint in drying felts, for instance. A raising element according to one embodiment of the invention makes it easier to align the ends of the product and to pass the joint thread in place, which substantially reduces the time required for the mounting of a felt, for instance, in the machine, and expensive down times are shortened. The invention, can be advantageously applied with different kinds of products, since the alignment strips and the locking strip can be dimensioned according to the properties of the product to be joined. By means of the invention it is also possible to join curved ends in an extremely advantageous manner.